Simulation of hurricane-type vortices in a general circulation model

A study of intense hurricane-type vortices in the ECMWF operational model is reported. These vortices develop around day 4 in the forecast and occur in the tropical belt in areas and at times where intense tropical cyclones normally occur. The frequency resembles that observed over most tropical regions with a pronounced maximum in the western North Pacific. The life time of the vortices and their 3-dimensional structure agree in some fundamental way with observations although, because of the resolution, the systems are less intense than the observed ones. The general large-scale conditions for active and inactive cyclone periods are discussed. The model cyclones are sensitive to the sea-surface temperature and do not develop with sea surface temperatures lower than 28–29°C. The dynamical conditions favouring cyclone development are characterized by intense large-scale divergence in the upper troposphere. Cyclogenesis appears to take place when these conditions are found outside the equatorial zone and over oceans where the water is sufficiently warm.

Estrogens, brain and behavior: studies in fundamental neurobiology and observations related to women's health

Mechanisms and consequences of the effects of estrogen on the brain have been studied both at the fundamental level and with therapeutic applications in mind. Estrogenic hormones binding in particular neurons in a limbic-hypothalamic system and their effects on the electrophysiology and molecular biology of medial hypothalamic neurons were central in establishing the first circuit for a mammalian behavior, the female-typical mating behavior, lordosis. Notably, the ability of estradiol to facilitate transcription from six genes whose products are important for lordosis behavior proved that hormones can turn on genes in specific neurons at specific times, with sensible behavioral consequences. The use of a gene knockout for estrogen receptor alpha (ERalpha) revealed that homozygous mutant females simply would not do lordosis behavior and instead were extremely aggressive, thus identifying a specific gene as essential for a mammalian social behavior. In dramatic contrast, ERbeta knockout females can exhibit normal lordosis behavior. With the understanding, in considerable mechanistic detail, of how the behavior is produced, now we are also studying brain mechanisms for the biologically adaptive influences which constrain reproductive behavior. With respect to cold temperatures and other environmental or metabolic circumstances which are not consistent with successful reproduction, we are interested in thyroid hormone effects in the brain. Competitive relations between two types of transcription factors - thyroid hormone receptors and estrogen receptors have the potential of subserving the blocking effects of inappropriate environmental circumstances on female reproductive behaviors. TRs can compete with ERalpha both for DNA binding to consensus and physiological EREs and for nuclear coactivators. In the presence of both TRs and ERs, in transfection studies, thyroid hormone coadministration can reduce estrogen-stimulated transcription. These competitive relations apparently have behavioral consequences, as thyroid hormones will reduce lordosis, and a TRbeta gene knockout will increase it. In sum, we not only know several genes that participate in the selective control of this sex behavior, but also, for two genes, we know the causal routes. Estrogenic hormones are also the foci of widespread attention for their potential therapeutic effects improving, for example, certain aspects of mood and cognition. The former has an efficient animal analog, demonstrated by the positive effects of estrogen in the Porsolt forced swim test. The latter almost certainly depends upon trophic actions of estrogen on several fundamental features of nerve cell survival and growth. The hypothesis is raised that the synaptic effects of estrogens are secondary to the trophic actions of this type of hormone in the nucleus and nerve cell body.

On a Gromoll-Meyer type theorem in globally hyperbolic stationary spacetimes

Following the lines of the celebrated Riemannian result of Gromoll and Meyer, we use infinite dimensional equivariant Morse theory to establish the existence of infinitely many geometrically distinct closed geodesics in a class of globally hyperbolic stationary Lorentzian manifolds.

A construção do princípio do cooperação na Pedagogia Freinet:uma prática em sala de aula do ensino fundamental

Cette recherche est ancrée dans les racines de la pédagogie de Célestin Freinet, un des plus importants éducateurs du XXème siècle, car ses propositions naissaient de la réalité de l élève lequel était, de ce fait, valorisé. Au début de ses recherches, Freinet s est rendu compte que pour pouvoir édifier une école qui, effectivement, atteigne les classes populaires, il devrait réaliser des changements dans le milieu scolaire. Notre travail le principe de coopération dans les actions développées par le professeur et ses élèves dans le quotidien de la salle de classe. Les décisions pour la réalisation de ce travail ont exigé, de notre part, une profonde et globale réflexion vis à vis des pas qui devraient être entamés, considérant que notre intention n était pas de faire une simple intervention dans le système scolaire avec une programmation pré-établie, sans instruments crées à priori pour le développement d actions dans le contexte scolaire. Comme questions principales nous pouvons souligner: Comment la coopération contribue pour le vécu des élèves? De quelle manière ce principe se réalise dans le quotidien de la salle de classe? Le principe coopératif, pourrait-il agir comme une alternative qui favorise la dynamique de la salle de classe et des relations entre les élèves? Le principe de la coopération exige la création d une ambiance en salle de classe dans laquelle il existe des éléments médiateurs dans la relation professeur-élève. Ainsi, l organisation de la salle a un caractère important; il faut considérer la participation des élèves dans la construction de ses connaissances. Pour cela, il est nécéssaire créer des structures qui doivent être complétées à partir de l activité des propres élèves. Dans la ligne de cette pensée nous avons, donc, comme objectifs spécifiques: 1) Investiguer, dans l action pédagogique du professeur, l utilisation de stratégies pour la consolidation du principe coopératif pour la salle de classe; 2) Faire une réflexion à propos de l organisation du travail coopératif développé par le professeur en observant comment celui-ci est réalisé en salle de classe; 3) Établir un répertoire des vécus de coopération construits en salle de classe par les élèves et le professeur. Ainsi, pour développer une interaction avec les sujets de la recherche [professeurs et élèves] des études ont été développés ancrés sur les principes de la recherche qualitative de type ethnographique pour considérer ce dernier un référentiel méthodologique plus indiqué à l utilisation des téchniques d observation, interviews et analyse de documents, car ces téchniques sont, traditionnellement, associées à l ethnographie. Cette recherche a pour but comprendre la vision de ce qui arrive quotidiennement dans la salle de classe observée et les multiples relations imbriquées dans le processus de motivation de l apprentissage utilisant la coopération

O conceito de morte: significações de professoras dos anos iniciais do ensino fundamental

Cette étude appartient à l un des principaux défis de l éducation dans l actualité qui est la production de connaissances concernant la mort comme objet d investigation théorique et empirique dans le domaine éducationnel. Des recherches récentes signalent le besoin d une éducation contemplant des études sur la mort et montrent l école tel qu un lieu de débats et reflexions à propos de ce thème. Cette reflexion est relevante et fondamentale, étant donné que la mort fait partie du cycle de la vie et se trouve présente dans les contenus scolaires des différents domaines de la connaissance. Ce travail a, donc, l objectif d analyser les signification attribués à ce concept mort et la relation qui s établit entre eux et la pratique des professeurs de l enseignement fondamental. Il adopte en tant que référentiel les principes de la recherche qualitative du type étnographique (André, Chizzotti et Meksenas), dans une approche socio-historique et en ce qui concerne la formation et le développement des concepts (Vygotsky, Kopnin, Guetamanova et Ferreira). La participation des professeurs a été faite par l observation participante, registres en cahier de bord et application d un instrument de construction de données pour l appréhension des significations attribués aux concepts qui sont à la base de la pratique de cinq enseignantes des premières séries de l Enseignement Fondamental d une école publique du réseau d enseignement de l État du Rio Grande do Norte située dans la Zone Sud de Natal. De ce fait, les analyses et les interprétations des observations de la pratique dans la salle de classe et des réponses aux quinze questions liées au thème ont permis de construire les significations des concepts qui appuient les pratiques enseignantes de ces professeurs, tout en mettant en relief la fragmentation et la désarticulation entre les expressions décrites dans les questionnaires et les pratiques développées en salle de clase. Ces reflexions mettent en évidence la nécessité de re-penser l articulation entre l énnoncé et la pratique des professeurs à propos de cette thématique au cours d une formation initiale et continue

Professoras e projetos: concepções e práticas no ensino fundamental

The discussion we have established in this study is about how the practice is developing educational projects based on work with because the methodological choice of the teacher. The study of an ethnographic qualitative approach was conducted with a group of six teachers in two public schools in School Administrative Zone north of the city of Natal / RN. Data were constructed from semi-structured, reinforced by the direct observation of the practice of teaching of teachers. The goals outlined were to identify the reasons why the option for the project, listing the benchmarks that subsidized their construction, the observation of everyday experience in educational planning and development of projects developed. In the light of information we can notice a complex and even contradictory, which is confusing the concepts and practices are weakened. The analysis revealed inconsistencies between theory and practice in working with projects, the fruit of little theoretical development of teachers. The adoption of the project as a methodological option has meant a change in direction of the effective action didactic. Reflects on this situation, it was concluded that there is a need to broaden the understanding of the significance of this type of work, covering the different dimensions that involve the practice of research, research and training of teachers. Even preventing the intentions and initiatives of the teachers, it must be emphasized is the process of learning within an approach that focuses the process of learning in multiple dimensions, inter-relational, both the capabilities of students in the areas of knowledge.

Mechanism of anticlastogenicity of Agaricus blazei Murill mushroom organic extracts in wild type CHO (K-1) and repair deficient (xrs5) cells by chromosome aberration and sister chromatid exchange assays

Agaricus blazei Murill is a medicinal mushroom native to Brazil. The present work assessed the clastogenic and anticlastogenic potential of organic extracts (ethanol and chloroform/methanol) from the lineage AB97/11 in chinese hamster CHO-K-1 (wild type) and CHO-xrs5 (repair deficient) cells using the chromosome aberration (CA) and sister chromatid exchange (SCE) assays. In these experimental conditions were observed: (a) anticlastogenic effect at concentrations of 0.06 and 0.09% of the EtOH extract and at the 0.03 and 0.06% concentrations of the C/MetOH extract in CHO-K-1; (b) absence of protector effect on CHO-xrs5 cells; and (c) absence of protector effect in the SCE assay. These results indicate that organic extracts of A. blazei lineage AB97/11 present bio-antimutagenic type protective activity. (C) 2003 Elsevier B.V. B.V. All rights reserved.

O pátio escolar do ensino fundamental como ambiente de brincar segundo as crianças usuárias

The intention of the present study was to analyze the adequacy of the playground of elementary schools, according to the point of view of the child student, direct user of this type of environment, what estimated its critical in respect to these spaces and aimed at to contribute for its improvement. Many studies have analyzed the quality of the physical environment available for activities of leisure in specific places for children, focusing in the influence of the physical space in the interpersonal relationships and the comfort and satisfaction generated by the physical characteristics of these spaces. Concern with scholar environment, specially the interest on playgrounds, has been subject of recent studies; however, little attention has been given to the opinion of the user-child in relation to this school environment. In this inquiry of the playground of two state schools of 1ª to 4ª series of elementary school in the city of Piracicaba, SP, was used: assystematics observations, photographic register of the studied environments, interviews with child-users and behavioral mapping. The main subjects resulting from the analysis of the interviews content were: adaptation, density and interpersonal relationships, and infantile confinement. The results revealed the unsatisfactory conditions of the courtyards, in respect to person-environment relationship. The children demonstrated to be critical, creative and responsible when answering questions related to the quality of the school courtyard. This finding confirms previous studies and leads to the conclusion that the child, as the direct user, should be included as an excellent source of consultation in the planning of the constructed environment

Uma justificava da validade do teorema fundamental da álgebra para o ensino médio

Among several theorems which are taught in basic education some of them can be proved in the classroom and others do not, because the degree of difficulty of its formal proof. A classic example is the Fundamental Theorem of Algebra which is not proved, it is necessary higher-level knowledge in mathematics. In this paper, we justify the validity of this theorem intuitively using the software Geogebra. And, based on [2] we will present a clear formal proof of this theorem that is addressed to school teachers and undergraduate students in mathematics

Simple derivation of general Fierz-type identities

General Fierz-type identities are examined and their well-known connection with completeness relations in matrix vector spaces is shown. In particular, I derive the chiral Fierz identities in a simple and systematic way by using a chiral basis for the complex 4 X 4 matrices. Other completeness relations for the fundamental representations of SU(N) algebras can be extracted using the same reasoning. (c) 2005 American Association of Physics Teachers.

Search for heavy lepton partners of neutrinos in proton-proton collisions in the context of the type III seesaw mechanism

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Introduction to Focus Issue: Statistical mechanics and billiard-type dynamical systems

Dynamical systems of the billiard type are of fundamental importance for the description of numerous phenomena observed in many different fields of research, including statistical mechanics, Hamiltonian dynamics, nonlinear physics, and many others. This Focus Issue presents the recent progress in this area with contributions from the mathematical as well as physical stand point. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4730155]

New higher-derivative R-4 theorems for graviton scattering

The nonminimal pure spinor formalism for the superstring is used to prove two new multiloop theorems which are related to recent higher-derivative R-4 conjectures of Green, Russo, and Vanhove. The first theorem states that when 0 < n < 12, partial derivative R-n(4) terms in the Type II effective action do not receive perturbative contributions above n/2 loops. The second theorem states that when n <= 8, perturbative contributions to partial derivative R-n(4) terms in the IIA and IIB effective actions coincide. As shown by Green, Russo, and Vanhove, these results suggest that d=4 N=8 supergravity is ultraviolet finite up to eight loops.

Ghost poles in the nucleon propagator in the linear sigma model approach and its role in pi N low-energy theorems

Complex mass poles, or ghost poles, are present in the Hartree-Fock solution of the Schwinger-Dyson equation for the nucleon propagator in renormalizable models with Yukawa-type meson-nucleon couplings, as shown many years ago by Brown, Puff and Wilets (BPW), These ghosts violate basic theorems of quantum field theory and their origin is related to the ultraviolet behavior of the model interactions, Recently, Krein et.al, proved that the ghosts disappear when vertex corrections are included in a self-consistent way, softening the interaction sufficiently in the ultraviolet region. In previous studies of pi N scattering using ''dressed'' nucleon propagator and bare vertices, did by Nutt and Wilets in the 70's (NW), it was found that if these poles are explicitly included, the value of the isospin-even amplitude A((+)) is satisfied within 20% at threshold. The absence of a theoretical explanation for the ghosts and the lack of chiral symmetry in these previous studies led us to re-investigate the subject using the approach of the linear sigma-model and study the interplay of low-energy theorems for pi N scattering and ghost poles. For bare interaction vertices we find that ghosts are present in this model as well and that the A((+)) value is badly described, As a first approach to remove these complex poles, we dress the vertices with phenomenological form factors and a reasonable agreement with experiment is achieved, In order to fix the two cutoff parameters, we use the A((+)) value for the chiral limit (m(pi) --> 0) and the experimental value of the isoscalar scattering length, Finally, we test our model by calculating the phase shifts for the S waves and we find a good agreement at threshold. (C) 1997 Elsevier B.V. B.V.

Estrutura em quilha Brasil central, uma feicao fundamental na geologia de Goias e Tocantins

The older Precambrian geological setting of north Goias/south Tocantins includes three areas of granite-greenstone terrains formed of medium-grade gneisses with associated greenstone belts and nepheline syenitic gneisses, separated by two orogenic belts composing a crustal-scale pop-up structure. The movements were firstly oblique towards NW along the northwestern NNE-SSW-trending Porto Nacional suture, and afterwards of essentially frontal type towards ESE along the southeastern Ceres suture of curved geometry with N-S direction at north and WNW-ESE at the south. The Porangatu block, limited by these sutures, was upthrusted over the neighbouring underthrusted blocks. Three principal kinematic phases are recognized along the orogenic belts. -from English summary